In a general form, the expression conveyors covers logically controlled conveyor techniques, such as roller conveyors, conveyor belts and chain conveyors for conveying piece goods.
In logistics, piece goods are transported between goods inwards and goods outwards inter alia on conveyors whose aim is to sort the piece goods and/or to distribute them, and/or to place them in store, to commission them or to supply them to workstations or machines for further processing. This relates in particular to piece goods from dispatch logistics, such as cartons, containers and packets, irrespective of whether these are in the singular form or are in the bulk material flow. The conveyors used are in general electrically powered and transport said piece goods by carrying them to the predetermined destination.
Small and medium-size logistic solutions with low-level requirements in the material flow for the conveyors have a restricted performance spectrum for good solutions, or, depending on the solution requirement, they suffer from high costs in the basic outlay, as well as costs resulting from individual configurations.
It is known for electrical microcontroller boards to be used on the conveyor. These carry out the function of operating the drives and the coordinating the material flow between the two conveyors in a predecessor/successor relationship. In general, the microcontroller boards are specific solutions from the conveyor manufacturer and are designed and built for this specific conveyor, that is to say they are not readily interchangeable. Furthermore, the use of microcontroller boards on extra-low-voltage drives (for example 24 V or 48 V) is restricted, as, therefore, is the performance of the drives and the load of the piece goods, as well.
The functionality of the known solution is provided by the controller board with an external bus coupling; extensions are, however, restricted within the predetermined product functionality and are possible only by the manufacturer, and extensions cannot be implemented by the customer. Although the basic complexity is low in this known solution, the system is, however, inflexible.
Furthermore, conveyors are known which are controlled by programmable logic controllers (PLC) which record the status of the conveyor and monitor the transfer of piece goods. In this case, low-voltage drives (for example 400 V) are also used, in addition to extra-low voltage drives. The power is supplied and signal connections made centrally or locally (bus-oriented). The functionality is defined individually in the PLC, and extensions to the logistic installation always require software changes in the PLC by the supplier or the customer. Because of the individuality that is required in some cases, the basic complexity is high, in particular for small to medium logistic solutions with low-level requirements for the material flow.
This solution also makes use of motor starters which are mounted decentralized on the conveyor or on the electrical drive. Depending on the functionality, these are completely controlled by central logic or have the capability to carry out the status monitoring for the drive, in order to reduce the load on the central logic. However, they do not have the capability to coordinate the material flow between two conveyors without superordinate logic with bus networking, for example control by a PLC.